Closure assemblies are known with a plastic cap that is mounted onto a neck, e.g. of a container. A tamper-evident structure is integrally formed as a part of the plastic cap.
A closure assembly is known from EP 1940699.
The long hollow pin portion of this type of cap is considered, at least for packaging some substances, to provide one or more advantages in view of product shelf life. For example it is considered that by effectively blocking a major part, or all, of the length of the channel by means of a seal at the lower end of hollow pin, the barrier properties of the closure assembly are enhanced. There is a more effective barrier between the packaged substances on the one hand and oxygen in the ambient atmosphere on the other hand, compared to a more common cap design where the hollow pin is absent and substance is present in the product passage. For example the hollow pin portion avoids that packaged substance is collected in the channel, which substance might be prone to drying and/or discoloring, e.g. in case of easily perishable food substances.
Whilst such advantages may exist, presently existing design of the hollow pin type cap are still deemed not satisfactory, e.g. in view of production costs, consumer handling, tamper-evident quality.
For example the presence of internal threading in the neck of the article hinders the passage of substance through the passage. Also the provision of threading on the circumferential face of the hollow pin portion is problematic in view of injection molding of the cap.
Another disclosure of a cap with hollow pin portion is in WO2014/187520. Here the skirt is provided with internal threading and the neck with external threading. Due to the presence of the hollow pin portion that extends to the level of the tamper-evident the injection molding of such a cap is problematic.